Canavan's disease is characterized by megalencephaly, leukodystrophy and early motor and mental retardation. On computerized tomography and magnetic resonance imaging, severe changes compatible with white matter disease due to demyelination is observed. It has been demonstrated that urinary N-acetylaspartate levels are increased because of a deficiency of aspartoacylase (N-acyl-L-aspartate aminohydrolase) in these patients. In this study, with the use of proton nuclear magnetic resonance spectroscopy, we were able to demonstrate elevated levels of N-acetylaspartate compared to choline and creatine in the frontal region white matter of three patients. The in vivo measurement of N-acetylaspartate, choline and creatine in the brain by magnetic resonance spectroscopy offers an additional noninvasive diagnostic test for establishing the diagnosis of Canavan's disease.